Chuck bushing for rock drills



invention is more particularly adapted for use in connection With drills of the stoper type. These drills are used in invertedposition and when equipped with chucks of the v type heretofore in use it has not been possible 5' to utilize the Weight fof the drill for retracting the Workin-gI imlplement as the chuck bushing merely acts as a guide for theworking implement Without being in any Way interlocl're'd thereto; In consequencex of this` censtruction when the drili is retracted the working implement frequently remains in the hole and it is thereforeneeessary-to-remove-the1 y lOvercome .the aforesaid objections. l Itenables the Weight of the` rock drill tobe utilizedfor vfreeing theI drill steel` fronrthe Vhole and thus eectsgafV considerable saving inthe matter of time. Y

5@ lclaimz, .1 l

a rock dri-1l, the combination of a fron-t head anda hrggedg Working implement, a chuck rotatable in the frontheadzand-termi- Y natin-g' at its front end in the same transverse 35' plane as the front head,` achuclr bushing eX- tending forwardly of the front kheadland having an extension threaded into the chuck, said chuck bushing having a bore for the reception of` the.l Workingimplement, a. recess tiva'nsverselyl through the 'chuck bushing land adapted tonen-rotatably engagetthe llugs of the Working implement al Wall. integral'vvith thechuck bushing forming a closurejfor the front end o the recess andgacting as anabutf Y k.fg ment or the lugs;a s ltin the Wall'toyenable i the lugs to enterithechuck bushing, said slotA beingA angularl-y disposed with respectA tof the recess, and cavitiesV opening from the SideA walls oftherecess f atpointsadjlacent. the lforu'o Ward extremity o-f the-recess. and` connecting said recess with the. sl'ot to permit of apar'- Y tial-revolutionciE the Working implement for carrying.theL lugs into' engagement iviththe recess, the rearvva-rdmost.portionsot said cav'- sai-ities lying well forwardly of Yany1 position which thelugs will occupy during thefnormal operation'` of the rock-drill, thus preventing Y vj y accidentalrelativerotation ofthe drill steel inthe chuck bushing.

605 In testimony whereof signed this,V

specification. p K 1 y Y Y Y- LEWIS-@.VBAYLES. 

